Research Highlights

Circular photogalvanic effect in two-dimensional Weyl semimetals ABSTRACT As a host of massless Weyl fermions, two-dimensional (2D) Weyl semimetals (WSMs) provide an ideal platform for studying exotic quantum phenomena in the emerging field of Dirac physics, including the circular photogalvanic effect (CPGE). Here, we report such behavior in a 2D WSM created in Bi0.96Sb0.04 thin…

Graphene/Si-quantum-dot heterojunction diodes showing high photosensitivity compatible with quantum size effect We demonstrate quantum size effect (QCE) of Si quantum dots (SQDs) in the device level under the detailed size variation, very promising for realizing the optoelectronic device applications of SQDs. For this, we report first fabrication of graphene/SQDs-embedded SiO2 multilayers (SQDs:SiO2 MLs)-heterojunction structures that…

For the application of graphene quantum dots (GQDs) to optoelectronic nanodevices, it is of critical importance to understand the mechanisms which result in novel phenomena of their light absorption/emission. Here, we present size-dependent shape/edge-state variations of GQDs and visible photoluminescence (PL) showing anomalous size dependences. With varying the average size (da) of GQDs from 5…

High photoresponsivity in an all-graphenep–n vertical junction photodetector Intensive studies have recently been performed on graphene-based photodetectors (PDs), but most of them are based on field-effect-transistor structures containing mechanically-exfoliated graphene, not suitable for practical large-scale device applications. Here, we firstly report high-efficient PD behaviors of chemical-vapor-deposition-grown all-graphene p-n vertical-type tunneling diodes. The observed unique PD…